This invention relates to optics and in particular to a lens for cameras. Recent advances in camera technology have materially reduced the physical size and weight of camera bodies. This reduction in size and weight has placed on the lens designer a corresponding challenge to reduce the size of lenses for such compact camera bodies. Many lenses having a fixed resultant overall focal length have been designed with increased members internal lens elements to reduce the overall size of the lens. However, until recently this reduction in size was not applied to zoom lenses. A difficult problem was that of so-called "soft-focus" in zoom lenses, particularly in the transition range from standard lens to telephoto sizes (i.e. 50 mm-105 mm). This problem precluded the use of zoom lenses in the wide angle range (i.e. 24 mm-38 mm) where edge distortion and coma abberation compounded the focus problem.
Moreover, consumer demands for camera versatility have given rise to requirements for zoom lens designs having effective ranges sufficient to eliminate the need for multiple lenses especially when travelling. One such requirement exists in the wide angle range 24-48 mm for use in out-door scenes as well as crowded in-door conditions. Such a lens would normally replace at least standard lenses yet offer comparable results. This invention is directed to an improved zoom lens of wide angle design that is extremely compact.
Accordingly, it is an object of this invention to define a novel zoom lens of compact size.
It is another object of this invention to define a zoom lens having good optical qualities yet operative in the wide angle range.
Still another object of this invention is to define a wide angle zoom lens of compact construction that eliminates the deficiencies of the prior art.